Subatomic particles give glimpse into sun’s core

First neutrinos detected from main energy source that powers our star

NEUTRINO NET Over 2,200 light-sensitive detectors line the inside of the nearly 14-meter-wide Borexino experiment in central Italy. The detectors, some of which are seen in this picture looking up inside the shell, have for the first time observed neutrinos from the center of the sun.

Borexino Collaboration

To peer into the heart of the sun, a 13.7-meter-wide stainless steel shell lined with over 2,200 light-gathering sensors hides deep under a mountain in central Italy. Known as the Borexino experiment, it watches for flashes of light from neutrinos, ghostly subatomic particles shot out of the sun’s core.

After seven years of searching, Borexino scientists report in the Aug. 28 Nature that the detector has for the first time caught a glimpse of the neutrinos cast out of the sun’s main nuclear reaction.

The sun supports itself by transforming hydrogen into helium. Neutrinos are one by-product of this alchemy. These particles have so little mass, they barely exist at all; roughly 10 billion trillion pass through the Earth every second without touching a single atom.

To spot such elusive prey, Borexino’s sensors surround a vat filled with 300 tons of a liquid hydrocarbon. Occasionally,

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